Decoding California’s redwood trees to bolster future forests

CALIFORNIA: The operating instructions for nature’s tallest and biggest trees have long been hidden inside their tiny seeds—until now.

On Tuesday (Wednesday in Manila), scientists announced an ambitious plan to decode the full genetic sequences of California’s two most iconic trees—the coast redwood and giant sequoia—to better understand and protect California’s grandest forests.

Why are some trees more resilient than others? Could they offer hope for future generations? That’s what the $2.6 million project, a partnership between UC Davis, Johns Hopkins University and the San Francisco-based Save the Redwoods League, aims to discover.

The two related species are stressed by loss of habitat and changing environmental conditions.

Environmentalists have fought to protect forests and combat climate change. But now it’s time for the next step—Conservation 2.0: Revealing the DNA of the hardiest trees could guide a rescue strategy for troubled forests.

“It is really easy to look for big trees in old forests and protect them,” said Emily Burns, director of science for Save The Redwoods and the lead investigator for the genome project.

“But something is hidden in the forest that we don’t understand nearly well enough—and that is genetic diversity,” she said.

When the project is complete in mid-2018, the team will have the so-called “reference genomes,” the Rosetta Stones of the two species. It will be made freely available to the public.

Then scientists can roam the forests in search of trees with a wide range of differing genes that help them fend off drought, disease, fire, pests and rising temperatures.

Genetic diversity acts as insurance against the total loss of an irreplaceable species.

Determining the complete DNA sequence of a single species has become almost commonplace, with comprehensive gene catalogs for hundreds of species ranging from microbes to humans.

Sequencing is a powerful tool to better understand human disease and design therapeutics, said professor David Neale, who will lead the UC Davis work in the university’s Department of Plant Sciences. It also has played a big role in agriculture, customizing the genetics of livestock and crops.

But the new redwood project, said Neale, is different, because it’s applying genetics to environmental restoration.

“These long-lived trees must survive where they’re born,” he said.

They share a common ancestor, diverging 50 million years ago.

The coast redwood is the tallest living tree on Earth, reaching up to 379 feet high. It lives along coastal California and the southwestern corner of Oregon.

The giant sequoia is the largest living thing by volume. The widest tree on record is 31 feet, the length of two Toyota Priuses. The largest weighs 642 tons, as much as 107 elephants. It grows on the western slopes of the Sierra Nevada Mountains.

Before commercial logging and clearing began by the 1850s, these massive trees occurred naturally in millions of acres in California.

For the genome project, scientists extracted DNA from seeds inside the cones of two old-growth trees, selected to act as representatives of their species.